1. Field of the Invention
The present invention relates to a plate bending machine and more specifically to a plate bending machine for manufacturing pieces of bent sheet metal.
2. Description of the Prior Art
The invention has been developed to resolve the problem of bending sheet-metal pieces of complex shape, such as for example, those illustrated in FIGS. 1a and 1b of the appended drawings.
Pieces of this type are frequently found in machines such as photocopiers, facsimile machines, and various electronic equipment. These products evolve rapidly, so that a manufacturer frequently changes models from one year to the next. Each new model is the result of a complete redesign even as regards the various sheet-metal pieces it contains.
These bent sheet-metal pieces are thus manufactured in relatively small runs, which do not therefore justify complicated and expensive tooling and dies: they are manufactured from pre-blanked pieces which are then subjected to various bending operations rather as in a workshop, making use of normal existing bending presses, for example, presses including fixed frames with a V-sectioned linear punches and dies movable with vertical relative movement towards and away from each other. Since successive bending operations, which are carried out from the periphery of the piece, cannot all be effected by the same die-punch pair, the manufacturer must have several presses available, each equipped with a different die-punch pair, or must replace the die and the punch whenever it is necessary.